One way to make an RF transformer is to take a section of twisted wire and a core and wrap the twisted wire around the core a predetermined number of turns. Such a transformer configuration has a plurality of parameters such as the inductance of each individual wire when wrapped around the core and a cross coupling inductance between each of the individual wires. Moreover, because of the widespread use of transformers, it would be desirable to have a model of the transformer and a method for making transformers so that performance of RF transformers can be optimized.
Typically, one method of obtaining information about RF transformers is to obtain many samples of wire and ferrite cores being used and to manually wind a transformer and then measure various parameters. This can be done repeatedly to eventually obtain a large amount of empirical data wherein this empirical data can then be used to design a desired transformer. This laborious method obviously suffers from the disadvantages that is difficult to optimize the design since no model is created and it is time consuming.
There currently exist other models for a transformer. For example, a low frequency model for a transformer may include two parallel inductors that are mutually coupled wherein a resistor is coupled across one of the inductors. In addition, a high frequency model may include a similar configuration but further including capacitors and/or inductors coupled across the mutually coupled inductors. However, no model is applicable for characterizing a transformer for both low and high frequency ranges.
Hence, there exists a need for an improved technique for modeling a transformer and an improved method for designing a transformer for enhanced performance.